(1) Field of the Invention
This invention relates to methods for separating components of mixtures by means of electrodynamic forces.
(2) Description of the Prior Art
Previously, separation of a mixture into its components has been accomplished by means of various methods including the following: mechanical separation, such as screening, sifting, gravity, pneumatic, etc.; chemical methods, such as floating, skimming, treating, etc.; electrical methods such as electrostatic drums, rotations, etc. All of these methods entail some combination of factors which involve acting on differences in size, size distribution, shape, moisture content, mass, charge, composition of matter, etc.
Masuda, S., Fujibayashe, K., and Ishida, K. "Electrodynamic Behavior of Charged Aerosol Particles in Nonuniform Alternating Fields and Its Application in Dust Control", Staub-Reinhalt. Luft. 30, 4-14 (1970), reported a method of transporting material by means of electrodynamic forces. However, separation of components has never been done using A.C. electrodynamic forces prior to applicants' discovery.
Bone char in its granular form was used to refine sucrose in 1828 in Paris by a confectioner named Dumont. For well over a century following Dumont's discovery, granular bone char was the main decolorizing agent in all sugar production.
Granular carbon, developed by the Pittsburgh Coke and Chemical Company, entered the market for sugar decolorizing absorbents in the 1950's and found wide application in the following decades. However, the advantages of granular carbon, particularly its intense decolorization powers and small capital equipment requirement, do not overcome the advantages of bone char which are absorption of organic and inorganic material.
Calgon Corporation uses a process of mixing granular activated carbon and char for decolorizing and deashing cane sugar liquors (U.S. Pat. No. 4,252,571, 1981). However, in this process it is necessary to separate service bone char and granular carbon.
Bone char and carbon differ greatly in their physical properties of hardness, attrition rate, particle size, shape and regeneration temperature. The loss of one component; i.e. carbon, at a greater rate than the other, is to be expected during service and regeneration. To make up such a loss a method is required to determine what percent of granular carbon remains in the admixture after regeneration. In addition, sugar refining requires a knowledge of activity of absorbents and the effectiveness of regeneration. Thus, separation of bone char and granular carbon components is greatly desired.
At present, a water separation procedure is employed to determine the percentage of components in a bone char-carbon mixture. The mixture is placed in a column and water is pumped upward through the absorbents, fluidizing the bed. The upper layer is presumed to be carbon and the lower layer char. The majority of the material in the middle of the column is a mixture which is discarded. The upper and lower cuts are analyzed. In discarding the middle layer, nonrepresentative results are obtained.
This method has inherent problems since bulk density and particle size will be the major contributing factors in water separation. Bone char and carbon particles have a wide overlapping of size and density. This results in a carry over of a mixture of the two components resulting in unacceptable char-carbon combination.